A putative receptor for angiotensin (mas oncogene from human) was detected by cotransfection and tumorigenicity assay of NIH-3T3 cells with DNA isolated from Human epidermoid carcinoma. These reports suggested that rearrangement of this gene after transfection resulted in the activation of the Human mas gene and subsequent transformation (Foci forming ability) of the transfected cells. Injection of these transformed cells into nude mice form tumors. Analysis of transformed 3T3 cells suggest that there is an increased synthesis of a protein capable of binding Ang II and Ang III. Immunofluorescence analysis using antipeptide-antibodies generated against the 1st and 2nd extracellular domains of the Mas polypeptide support the presence of an increase in receptor synthesis in transplanted 3T3 cells. Taken together, these results suggest that the mas gene product participates in cell growth and proliferation. Whether the Mas protein functions as an angiotensin receptor or as a binding site for growth factors stimulating the binding of angiotensin, or whether the increased binding of angiotensin and cell growth resulting from the presence of Mas is cell-type selective is not fully understood. Therefore, the objectives of this proposal are (i) to characterize the binding of angiotensin in NIH-3T3 cells transfected with the human mas gene, (ii) to determine the role of mas gene in regulating cell growth and proliferation, (III) to determine if the cells response to mas expression is cell-type or mechanism specific, and (iv) to correlate mas gene expression and angiotensin receptor activities in uteri of pregnant and non-pregnant rabbits. Students (both graduate and undergraduate) are expected to participate in all aspects of this proposal.